556 REPORT— 1886. 



6. Exhibition and Description of Miller's portable Torsion Magnetic Meter. 



By Professor James Blyth. 



The armature is formed of five small bars of soft iron, 5 mm. long, and weighing 

 1 gramme. 



The index wheel has its rim divided into y|ot^S) ^^^ carries the outer end of a 

 flat spiral spi'ing, the inner end of which is firmly fixed to the long axis which 

 carries the small armature bars. A fixed pointer projects from the ends of the 

 case across the edge of the disc, and another pointer is fixed to the armature axis. 

 In the normal position the pointers both point to the zero of the scale. 



When the armatures are placed in a magnetic field they are turned roimd and 

 are brought back to their zero position by coiling the spring through a definite 

 angle depending upon the strength of the field. A constant is determined for the 

 instrument by experiments in a field of known strength, or if necessary it can be 

 empirically graduated. 



It is hoped that the instrument will be found of service to makers of dynamos 

 for finding the strength of the field in various parts, and also for finding the best 

 forms of pole pieces. 



There was also exhibited a form of small attraction magnetometer. 



7. On the Protection of Life and Property from Lightning} 

 By W. McGregok. 



The paper proposes the formation of a committee with the following aims and 

 objects: — 



(a) To travel, and by means of illustrated lectures or papers to awaken general 

 interest in this vital subject. 



(h) In a plain journal to publish details of any serious disasters, with pro- 

 fessional opinion in language to be easily understood by the public. 



(e) To provide scientific advice and co-operation. 



(d) To bring about esijrit de corps amongst architects, engineers, builders, 

 and manufacturers of Ughtning conductors. 



(e) To advise and encourage authorities whose duty it is to protect life and 

 property to employ the means provided by science. 



(/) To encourage and support insurance companies to insist on employment of 

 these means, and to frame a clause in the policy to enforce proper inspection and 

 testing. 



{(/) To insist upon architects showing the arrangements of metal in buildings, 

 the uatm-e and position of the means adopted for protection against lightning. 



(h) To investigate (if not already known) the cause why in a general assembly 

 it occurs that men are more frequently killed or injured than women, and why 

 certain localities are more specially selected by lightning. 



{{) Finally to enable the society, branch, or committee to illustrate to the 

 public the practicability of secm-ing perfect safety at a minimum cost, and to 

 have the lightning conductors or system of conductors as easily governed and 

 tested as the gas-pipes, and the tests read ofi' as simply and inexpensively as the 

 reading of the meter, which can be accomplished by observing the following 

 rules : — 



(1) Employ none but qualified persons. 



(2) Avoid extra expense and trouble by having testing-wires fixed at once. 



(3) Do not grudge an extra length of conductor if required by the nature of the 

 soil near the building. When you are selecting land for cultivation, or soil for 

 certain plants, some trouble is involved ; let the same interest be taken in the spot 

 where the earth terminal is to be laid. 



' See also pamphlets by same author oa Protection of Life and Property from 

 LigMning and Loss of Life and Property by Lightning, and paper contributed by 

 him to the Bengal Asiatic Society. 



